Method of heat-treating uranium-silicon alloys



Aug. 4, 1959 s. T. zEGLx-:R 2,898,252

METHOD OF HEAT-TREATING URANIUM-SILICON ALLOYS Filed'auly s. 1951Y IN VEN TOR.

cooled.

- p 2,898,252 y `Patented Aug. 4, 1959 J 1 to a maximumitemperature of 550 C., theiheatin'g period to the higher temperature being carried out with- Y2,898,252 in `ilve minutes, while twenty minuteswere allowed f Y 1' f' f each-'time .for cooling to 100 C. The tests were car- Y- 5 riedout .fusing `a total of.509, cycles with intermediate 'l v l f 1= l "i examinations. The ,results of thes`e= experiments;i are Sylvester T. Zegler, Chicago, lll.,.assignor to the United compiledinthe following table.

States of America as represented by the United States Atomic Energy Commission lo Y -Treit- Percen:J Chaligi in Original Application July s, 1951, serial No. 234,919- Compound Tlat engi t- 8 ClalmS.' (Cl. 14S-'13) secs. 100 cycles 300 cycles 509 cycles This invention deals with alloys, in particular with 1g i 21g; il

uranium alloys, and with a process of manufacturing L44 4-03 5-7 sai a oysz 60 0.16 0. 51 0.83

The main object of this invention is a uranium-base 12g 2g? 3g?, 05

material which is of :great dimensional stability and 5 442 10135 15:9

which 1n particular does not elongate or otherwise g g' g3g 1l5fl,

permanently expand after heat-treatment so that it is 001% s1/U a0 011s -i04 -isi useful as structural material when 1t is exposed to peri 037.723 SVU 120 0 15 0 68 1.12 odic temperature changes.

The uranium-base material of this invention is also suitable for use in a neutronic reactor of the type de- 25 It will be seen from this table that after a treatment -b of twenty seconds in the beta phase a contraction (negagiad thggglnddaplllelgner oflgperrglft aa tive elongat1on) rather than expansion took place when granted as AU'S atellt NO 2 708 656 on May 17 1955 the alloy was subjected to the cycling treatment used.

It has been found that by incorporating a' Smali The results of the lower half o f this table were quantity of silicon into the uranium metal and subjcct- 3 plotted m a dlagram m Whlh the tlmes of belg-Heap ing the alloy obtained thereby to rolling in the alpha ment are shown on the absclssa and theflongatlon (m phase, which is below about 660 C., heating the rolled rcend). Utl thIhheat'tl-eatedblljanlm'slllcln rolls n metal at beta phase-temperatures, which are between e or ma e'. e curves o ame. as s. own m e about 660 and 770., C .and then quenching the alloy attached drawing, all cut the zero line, which represents for example, by immersion in water a material is ob 35 no elongatlon. or contractlon durmg thermal gyclmg at tained that is of great dimensional stability and in parthe Same pomt. namely at that cmespqndmg to .a ticular does not expand when alternately heated and beta'treatment um? of llfteen secomls' Thls means ln other words, that 1f the rods are subJected to a temperl ture of 700 C. for fteen seconds an absolutely di- A silicon content of from 0.01 to 0.1% by weight a was found to have this favorable effect; however, from 40 menslollall'y Stable matenal ls Olllilallled b 0.05 to 0.07% by weight of silicon is the preferred Il: wlll be undersllthatt s mventlon 1S.not to e range and 007% has given the Optimal results The limited to the details given herein but that 1t may be binary uranium alloy containing 007% by weight of mlled Wlhm tte scope of the appended clalms' tiscaime is: silicon showed even a contraction when subjected to a the above-mentioned heat-treatment provided that the A procfa'ss for manufalclllmlg uranlulll'base m? betamreatment was Carried out long enough FOI. many terial of a high degree of dimensional stability,- and in uses of uranium a contraction under the .influence of particular fret fltlm thermal epanslpn comprlsllg n corporating 1n o e uranium s1 icon 1n an amoun suc tglitgnheatmg and coohng 1S less oblectlonable than as to obtain a content of from 0.01 to 0.1% by weight, rollin the allo obtained at a temperature of below ln .Ordel' to Sllow .the elle of slllconand' also of 50 660 gC beta-li/eating said alloy to a temperature of variation 1n heating times in the beta phase, a number b tw "660 and 770, C and uenchin the allo of comparative experiments were carried out with a e een q hg il. y' uranium-silicon alloy having 0.07% by weight of t The pl-focess oosclm 017,; hrel/egt .s lcon consilicon on the one hand and with pure uranium on the all; lhnges rroensls f Claim' 1 vovheein the silicon com other hand. In all instances the uranium and uranium 55. tentis Owoy Weight logdirrlpewy gieaglthg 29' lerr v4. The process of claim 1 wherein the material is rolling step, the rods were immersed in a lead bath of ToledTllteablgo Og'claim 1 wherein beta heatin is 600 C. for ve minutes in order to preheat the metal '.ed flat about 700 C for at least ten Secods and subsequently to obtain the beta phase temperature carn Thou ro ess of claim wherein beta heatin is in a shorter period of time. Thereafter, the rods were d e tpforcfteen seconds g immersed in to another lead bath of 700 C. and left caf/,neThou Ces of claim 1' wherein the uenchinu is there for periods of time varying within a range of bed e Itmviths Water of room tem mugre D tween two and one hundred twenty seconds. The samcagrleThou oc Ss of claim 1 Whereinpthe qunched ab ples were then quenched in -water (room temperature) e pr e h 575, C yand iinally annealed for two hours at 575 C. in an atloy ls atllnealld forf llprgxlmately two Ours at mosphere of argon gas. The annealing step is not m ana Osp elec go References Cited in the tile of this patent UNITED STATES PATENTS Van Arkelv Oct. 5, 1926 (Other references on following page) obligatory in order to obtain the properties desired.

The rod samples thus treated after centerless grinding to provide smooth surfaces were examined for dimensional stability. For this purpose they were cycled 1'6019 31 repeatedly between a temperature of C.

-v UNITED STATES PATENTSv 1,719,975 Gero July 9, 1929 2,574,626 Daane et al.- Nov. 13, 1951 Daane et al. Nov. 13, 1951 *1"946'fk1`ec1ass' November 25, 1946, pp. 12, 13; 1'4

especially relied upon; entire publication contains 20 pages.

Wilson et al.: X-Ray Studies of Alpha, Beta and Gamma Uranium, AEC Document No. ABCD-2046, declass. June 9, 1948, page 3 especially relied upon; entire document contains 8 pages.

Zachariasen: The Crystal Structure of Uranium Silicides and of CeSi'2, NpSi2 and PuSi2; AEC Document No. AECD-2092,/dated January 6, 1948, declass. 

1. A PROCESS FOR MANUFACTURING URANIUM-BASE MATERIAL OF A HIGH DEGREE OF DIMENSIONAL STABILITY, AND IN PARTICULAR FREE FROM THERMAL EXPANSION, COMPRISING INCORPORATING INTO THE URANIUM SILICON IN AN AMOUNT SUCH AS TO OBTAIN A CONTENT OF FROM 0.01 TO 0.1% BY WEIGHT, ROLLING THE ALLOY OBTAINED AT A TEMPERATURE OF BELOW 660*C., BETA-HEATING SAID ALLOY TO A TEMPERTURE OF BETWEEN 660* AND 770*C., AND QUENCHING THE ALLOY. 